TypoScript setting
`plugin.tx_indexedsearch.settings.blind.numberOfResults`
receives a comma separated list of integer values. If number of results
sent in request does not match any value from this list,
default (first) value will be used to keep DoS attack protection.

Values from `plugin.tx_indexedsearch.settings.blind.numberOfResults`
are used as options in the select box in advanced search mode.
To keep backward compatibility default values are 10, 25, 50 and 100.